How to install a lawn irrigation system attached to recycled water?

[TimGeo]

Well, It's been a while since I've been in the workshop, not much has been going on in the landscaping department, the only thing I've really done since last time was renovating my front lawn, and in the next week or so I'll be doing to nature strip and if I have enough time in the season I'll do the back yard, including some levelling and any modifications.

Today's plan is to figure out irrigation for the lawns, and eventually the whole property, in which case I plan to have stuff set up so that when I'm ready i can just rig up the next zone and plug it in to the existing box which would have solenoids ready to go.

As this will be my first time ever setting up irrigation, I've got a few questions and some confusion about parts.

I did a pressure test on my taps a while ago which was around 400kpa (60psi) and filled a 20L bucket in approx 30 seconds. However this was a while ago and now that I think about it, I did this on the taps at the rear of the house, where I probably should have done it at the main tap, so I'll be doing the test again before anything cos I feel that it might be a bit low.

To keep it simple I'm just starting with the nature strip then I'll move onto the larger front yard etc. But I'm trying to understand which pipe is the must suitable throughout the system. I will be teeing off the recycled water (Purple PEX SharkBite pipe) and I will likely need a filter as I often find my hose triggers getting clogged with unusual debris and have to replace them every few years.

As for the pipe from the tee, I often see that black with blue striped pipe which looks quite beefy that runs from the supply to the solenoids but I'm not clear on diameter, perhaps I can get some advice on pipe selection.

As for running the sprinkler system for the nature strip, I've seen pipe run directly into sprinklers in line, I've also seen setups with an articulated riser. I guess for the extra cost of adding more potential places to leak it's not worth adding the articulated risers?

I'll post back with my water pressure and LPM but if I could get some information to make selecting the right products easier that would be a great help! 

I can only take a guess and say to run 19mm or 25mm poly pipe from the supply to the solenoid bank, then run 19mm poly throughout the system and whatever sprinklers I decide to use which should match the pipe?

thanks

[JacobZ]

Hi @TimGeo,

Welcome back to the Bunnings Workshop community, it's great to see you're getting stuck into some new projects after a year-long hiatus.

I suppose the best thing you can do for myself and our members to assist is to plot out the area with some measurements, the likely location of the irrigation lines and the location of your taps. If you can give us a rough plan on paper, this will help us to offer our best advice.

Most residential applications don't require massive irrigation lines, meaning 13mm Poly Pipe or 19mm Poly Pipe are the best options to look at. The black and blue poly pipe, like this 25mm Blue Poly Pipe, this 32mm Poly Pipe, and this 50mm Poly Pipe, are usually used for larger irrigation systems, such as sport fields, botanical gardens and farms, where a lot of water needs to be moved around.

The 13mm and 19mm poly pipes will connect into residential taps very easily with a variety of accessories to make this as easy as possible. There are filters such as this 13mm Poly Inline Barbed Filter and this 19mm In-Line Barbed Filter which can also be easily integrated into your system.

For lawns, pop-up sprinklers are definitely the way to go as they will activate when water is flowing but be concealed below the level of the grass when it comes time to mow.

Having not installed irrigation systems myself, a lot of my knowledge about irrigation systems comes from our guides and our suppliers' resources. Have a look at Pope's irrigation DIY guides, Holman Industries Pop up Sprinklers and Nozzles and our guides on How To Plan An Irrigation System and How To Install An Irrigation System.

Once you've gotten back to us with a basic plan on a page, I am happy to assist wherever I can to design a system that will work for you.

Jacob

[TimGeo]

Hi Jacob,

Thanks for the warm welcome, it's been a slow year for progress that is for sure! But time to motivate myself and start working on something. At least I can say that I have done something 😅

So below is my drawing along with the front lawn for reference, looking at the image I would like to run irrigation around the perimeter of the lawn and the nature strip, if I need to cut into the middle to install a couple of 360° pop-ups, so be it. 

I had installed a tap on the side of the house on a sharkbite Tee that reduced the purple recycled water (i think 22.7mm, I'll have to find the offcut and measure it...) down to copper, so I could rearrange what I had initially done and install another sharkbite Tee where the reducer is in place, this way I can bypass the copper pipes and elbows where Friction loss will occur and run the 19mm poly to the solenoid bank.

I had researched the rainbird brand and  I am pretty happy with the "U-series" heads.

The nature strip is fairly straight forward, if you think a better option would suit, please let me know,

•19mm poly pipe from the solenoid under footpath to a Tee so there's two parallel runs on each side of the area

•1800 series sprinkler bodies

•90° U-10Q for each corner (2.6m radius)

•180° U-10H spaced aproximately 2.6m apart (2.6m radius)

For the front lawn, the shape is a little complicated, along the straight edges is easy enough, 

•Each corner U-10Q @2.1m radius or the U-15Q at 3.9m radius, if I go with the U-10Q I'll probably need another sprinkler head or two for more coverage

•The garden bed side (right) I'll need the U-10H at 2.1m radius

•The Front would be 2.6m apart (2.6m radius)

•The curves are a little complicated, not sure which style and how many as the only other angle I can use is the 120°  which doesn't cover the area properly, which means I'll need more, 

•In the middle I'll need some 360° heads to reach every other sprinkler for even coverage.

I would install the filter and check valve before the solenoid bank, and the master shut off valve i might install either at the solenoid bank or install a box in the garden bed where the main Tee is installed.

As for power, I guess I'll run some conduit underneath along the merbau fence and up the wall, and do a run to the garage via the roofspace fir the controller.

 

 

  

   

[TimGeo]

Here I plotted out the nature strip with 2.1m radius sprinklers, the top image is just to show the overlap between two sprinklers, the bottom image shows the entire area with the corners being 2.6m radius to reach the corners, there will be a little overspray due to the spacing of the sprinklers which I tried to minimise as best I can.

using this information how can I make sure that all this is all going to fit into one zone? do i just add all the individual sprinkers' Litres per minute and as long as they are less than the supply flow rate i should be ok?

if so then all of the values as per the data sheet come up to 25.9 Litres per minute, is there any other parameters to consider to ensure adequare flow?

[JacobZ]

Hi @TimGeo,

You've clearly done your research, and you have a much better understanding of the space than I do, so I think you should stick with your plans.

Looking at your plans, to ensure adequate flow, it would definitely be worth using 19mm poly.

Yes, you will just need to add the total flow rate requirements for each head. In your example, the total combined flow rate of 25.9 L/min must be less than your available supply flow rate. You can measure the flow rate directly at your tap or irrigation line by timing how long it takes to fill a container of known volume. You can use this Flow Rate Bucket Test Calculator to confirm the flow rate.

Leave a small buffer (e.g., 10-20% of your supply flow rate) to account for variations in pressure or potential system inefficiencies from things like friction loss, elevation loss and pressure loss from fittings like tees and elbows. 

If your flow rate doesn't meet the requirements of the zone, you may need to split it up.

It is likely worth starting with the irrigation line for the nature strip as it is less complex. This will help you have a better understanding of what you're working with before you move on to the front lawn, which has more complexity.

Let me know if you have any further questions.

Jacob

[TimGeo]

Thanks Jacob,

I might double check my plans with an irrigation installer to make sure the decisions I've made all marry up,

but i think i've planned the front lawn. seen below are the sprinklers I think will be the best fit, on the left curve i decided to go with the High-Efficiency Variable Arc Spray Nozzles, this way I can go beyond the quarter or half radius but keep the garden bed from getting too much water, the rest of the sprinklers probably the U series half and quarter radius, and finally one full radius in the middle to cover the area that the rest couldn't reach, the last image is just an overlay of all of them combined

I did another flow rate rest and it was consistent with the previous one, at 31 l/m

if I added them correctly it seems that the zone would be 33.7L/m, just a bit over the limit, which means i might have to make 2 zones or change the sprinkler heads to make them more efficient so they use less water. at least I have something to work with so I can refine the system. stay tuned!

[TimGeo]

Thanks Jacob,

I might double check my plans with an irrigation installer to make sure the decisions I've made all marry up,

but i think i've planned the front lawn. seen below are the sprinklers I think will be the best fit, on the left curve i decided to go with the High-Efficiency Variable Arc Spray Nozzles, this way I can go beyond the quarter or half radius but keep the garden bed from getting too much water, the rest of the sprinklers probably the U series half and quarter radius, and finally one full radius in the middle to cover the area that the rest couldn't reach, the last image is just an overlay of all of them combined

I did another flow rate rest and it was consistent with the previous one, at 31 l/m

if I added them correctly it seems that the zone would be 33.7L/m, just a bit over the limit, which means i might have to make 2 zones or change the sprinkler heads to make them more efficient so they use less water. at least I have something to work with so I can refine the system. stay tuned!